@article{JRAM_1883__94_148523,
     author = {J.P. Gram},
     title = {Ueber die {Entwickelung} reeller {Functionen} in {Reihen} mittelst der {Methode} der kleinsten {Quadrate.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {41--73},
     publisher = {mathdoc},
     volume = {94},
     year = {1883},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1883__94_148523/}
}